Machine key adaptation



Jan. 7, 1969 R. R. DOWNIE MACHINE KEY ADAPTATION Sheet Original FiledAug. 10, 1964 INVENTOR.

.0 (QIQPIDU'SIPKUOEQ Jan. 7, 1969 Z of 2 Sheet Original Filed Aug. 10.1964 mwn INVENTOR.

United States Patent This invention relates to means for adaptingcertain hexagonal types of machine keys to the rectanguler keyspaces ofstandard machine keys, so that a rigid connection is effected.

This application is a continuation of my application Ser. No. 388,456filed Aug. 10, 1964, now abandoned.

Objects of the invention are to provide, in keyspaces of rectangularshape, for vertical and lateral impacting pressures automatically andproportionally adjusted as between upper and lower keyways; for the useof shimming at one or more keyway faces with rotatably distributedpressuring effect at all faces; and generally, by residual impaction atall working faces, to prevent all relative movement of the faces andthus to obtain durability to the keyage under hard reversing duty.

Reference is here made to my copending applications, Ser. No. 294,369,filed July 11, 1963 and now Patent No. 3,362,734, and Ser. No. 325,808filed Nov. 19, 1963 and now abandoned, for more detailed descriptions ofthe hexagonal key types with use of which the present application isconcerned. The keys are referred to herein respectively as the expandinghexagon and the wedge hexagon types. The same reference is made for afuller explanation of an inherent and well-known dithculty encounteredin the operation of the rectangular sectioned standard machine keyscurrently in general use. In summary that difficulty is that, underheavy pulsative or reverse impact duty, the rectangular keys all beginto loosen, that is begin slowly to fail, with the first few hard andsharp transverse loadings; this even though the maximum shear forceapplied is but a minor fraction of the actual shear strength of the key.The two hexagonal keys referred to, with their triple-wedging principle,to tactile Wedges engaging the keyed members and a longitudinal wedgingof either horizontal or vertical action for the seating of the tactilewedges, cannot be made to fit or work with direct bearing in theexisting standard keyways; this because of the parallel sidewalls andthe consequent compartmentation of lateral spreading forces of the keyin each keyway. The present invention, at the cost of certain smallauxiliary parts, makes the hexagonal keys effectively applicable inexisting machines without the relatively very large expense and delaywhich would be entailed by disassembly and the cutting of new keyways orthe substitution of new keyed members having appropriate wedgeformkeyways.

In the accompanying drawings, for clarity, longitudinal slope angles areexaggerated, shim thicknesses are more substantial than would benormally required, the members are varied slightly in length and thekeys are shown as gripping at positions other than their mean or nominalpoint of tightening range. As to reference characters, capital lettersare used, with arrows to indicate physically separable members andnumbers are used to indicate areas, lines and reference points.

FIG. 1 is a side elevation of a representative form of wedge hexagon keywith adapter elements in place and showing in section adjacent portionsof a hub and shaft keywayed for a square tapered standard key. Portionsof the near side upper and lower adapters are broken away at the frontor right hand end of the key.

FIG. 2 is a plan view of the structure of FIG. 1 but omitting the huband with a portion of one upper adapter broken away at the right handend.

FIG. 3 is an enlarged cross section on line 33 of FIG. 1, with a portionof the key broken away at the right hand side to show the adapter piecesmore clearly.

FIG. 4 is a bottom view of the near-side upper adapter of FIG. 1.

FIG. 5 is a bottom view of the near-side lower adapter of FIG. 1.

FIG. 6 is a side elevation of a second form, a straight, split,expanding hexagon key with adapter elements in place and, in section,adjacent portions of hub and shaft keywayed as for a straight squarestandard key. Portions of the near side upper and lower adapters arebroken away at the right end.

FIG. 7 is a plan view of the structure of FIG. 6 but omitting the hub,and with a portion of one upper adapter broken away at the right end.

FIG. 8 is an enlarged view of the structure of FIG. 6, partially insection on line 8-8. A portion of the key itself is broken away at theright.

FIG. 9 is a transverse view of a third form, taken at a positioncorresponding to that of FIG. 8. A portion of the key is broken away atthe right. (Longitudinal views of this construction are omitted as beingthe same as FIGS. 6 and 7 except for the addition of the lateral fillerplates to be described.)

FIG. 10 is a transverse view of a fourth form, likewise taken at the endof the hub, the view corresponding to FIG. 3. A portion of the key isbroken away at the right. (Here also longitudinal views are omitted asbeing similar to FIGS. 1 and 2 except for the addition of certain shimsto be described.)

Now referring more particularly to the drawings, in the firstconstruction, FIGS. l5, A is a wedge hexagon key, B and C are upper orhub keyway angular fillers, herein called adapters, and D and E arelower or shaft keyway adapters. F and G are respectively adjacentportions of the hub and shaft in which a standard square taperedkeyspace is formed. 11 is the median line or longitudinal axis of thekeyage, 2 (FIG. 3) is the arc of the shaft surface and hub bore, 2a is ahorizontal line through the lip points of the keyways, and 3, 4 are theinner edges of the upper adapters B, C, which edges are parallel as arethe corresponding edges of the lower adapters D, E. 5 (FIG. 1) is thesloping top surface of the key A, and 6 is the floor of the upperkeyway, these being in parallel planes, 7, 8 and 7a, 8a are respectivelythe vertical outer faces and top faces of the upper adapters B, C, inpressured contact with the sidewalls and floor of the upper keyway.Points 9, 10 (circled, FIG. 3) indicate the lip lines of both keyways.7b, 8b are the triangular bottom faces of the upper adapters, located inor slightly above 2a, the plane of the lip lines 9, 10, 11, 12 (FIGS. 1,2) are the lines of intersection of upper and lower flanks of the key.13, 14 are respectively the parallel planes of the shaft keyway floorand the bottom surface of the key.

15, 16 and 15a, 16a are respectively the vertical outer faces and bottomfaces of the lower adapters, in pressured contact with the side-wallsand floor of the lower keyway. The rectangular axes 1 and 2a (FIG. 3)divide the keyage into four quarter-areas or quadrants for conveniencein referring to adapter locations. Similar axial division is consideredto apply also to the other three forms, FIGS. 8, 9 and 10 Where the twokeyways differ in width, as in FIG. 10, the horizontal axis isconsidered to be located in the plane of the lip lines of the widerkeyway.

In the second construction, FIGS. 6, 7, 8, H and I are the halves of anexpanding hexagon key in set position in a square straight standardkeyway. K, L are the upper adapters and M, N the lower, all four ofwhich may be alike. P, Q are respectively adjacent portions of hub andshaft. 3131 is the median line or longitudinal axis of the keyage and31a (FIG. 7) the pitch plane of the interfitting serrations of thehalves. 32 (FIG. 8) is the arc of the shaft and bore surfaces. Points33, 34 (circled, FIG. 8) represent the lip lines of both upper and lowerkeyways. 33a (FIG. 6) is the line of intersection of the nearside upperand lower flank planes and nominally coincides with the keyway lip line.(It may rise or fall slightly as the key finds its pressure balance inthe specific keyage.) 35, 36 are respectively the parallel top surfaceof the key and the upper keyway floor. 37, 38 and 41, 42 are the outervertical faces respectively of the upper and lower adapters; 37a, 38aand 41a, 42a being the respective horizontal floor-contacting faces; allbeing in pressured contact with the respective keyway surfaces. 39, 40are respectively the parallel but non-contacting bottom key surface andthe shaft keyway floor.

In the third construction, FIG. 9, R, S are the halves of an expandinghexagon key, T, U and V, W are lateral fillers respectively in upper andlower straight flat standard keyways and X, Y are respectively adjacentportions of the hub and shaft. 5151 is the median plane or axis of thekeyage, 52 is the arc of shaft surface and hub bore, 53, 56 arerespectively the upper and lower keyway floors, and 54, 55 and 57, 58are the outer faces of the four lateral fillers. The key and triangularadapters are of the same type as those of FIGS. 6, 7, 8, in similarlyset position, adjusted in size to suit the construction and so need noparticular description.

In the fourth construction, FIG. 10, Z is a wedge hexagon key. AA is afloor shim in the upper keyway. AB, AC are lateral shims in the lowerkeyway and AD a floor shim, likewise in the lower keyway. AE, AF areadjacent portions respectively of hub and shaft. 6161 is the medianplane or axis of the keyage and 62 is the arc of shaft and bore. Incontact with the upper keyway floor, the sloping top surface of thefloor shim AA is clearly shown. 65, 66 are the outer vertical faces ofthe upper adapters. 67 is the lower face of floor shim AD, in contactwith the shaft keyway floor. 68, 69 are the outer faces of the lateralshims, in contact with the keyway side walls. The key and triangularadapters are exactly like those of FIGS. 1-6, are in similarly setposition and so need no particular description.

In the FIG. 10 construction, illustrating a combination of both verticaland horizontal shims, the particular keyway condition assumed to be metis that of a hub keyway of excessive depth and a shaft keyway which hasbeen refinished in maintenance to oversize dimensions in both width anddepth, thus requiring, for repair in the rectangular key system, anoversize key especially offset or shoulder-ground to fit the mismatchedkeyways. Conversion to a standardized hexagonal key, with its regularcomplement of standardized adapters and using staple shim stock for thestraight dimensional make-up, offers, in addition to the systemadvantage of full impaction, the economy of avoiding special machiningof the key. The versatility here illustrated is derived from the sameinherent qualities of the pressured hexagonal keys as the direct faceshimming of those keys, namely the angular incidence of pressure faces;permitting insertion, adjustment and solid equalized residual impaction,and thus the retention and preservation, of the make-up pieces.

As to installation, in the first and fourth constructions the key andsupplementary pieces are inserted and arranged manually a short distancein rear of the desired final gripping position, the pieces beingsomewhat in advance of the key itself; and the key is then hammer-driveninto place. In the second and third constructions, FIGS. 6-8 and 9, thekey, in contracted lateral adjustment, is inserted, with itssupplementary pieces, and placed manually at the approximate desiredfinal position, allowance being made for the appropriate oppositedriving movements of the halves and for the normally lesser movements ofthe contacting auxiliary pieces. Two precautions are of sufficientpractical importance in each installation of either key type to justifystatement: (1) Before driving or setting of key, see that the specifickeyways are centrally co-aligned vertically, for true bearing at eachface. Adapters may be filed appropriately if necessary for correction ofbearing. (2) After setting, see that complete floor clearance has beenobtained at top and bottom faces of the key.

In actual operating principle, after installation, the two types of keysare substantially the same. In both cases solid residual pressures,developed at the four working faces by the setting of the key, maintainall contacts with sufficient reserve pressure to prevent relativemovement of surfaces regardless of frequency of pulsations or directionreversals of the operating load imposed by the displacement forces inthe keyed members.

In all of these adaptive constructions the radial and tangentialcomponents of the key face forces are necessarily separated in theirapplication to the rectangular keyway, the radial being exertedexclusively upon the floors and the tangential exclusively upon thewalls. But the combined origin of the diverse forces precludesinterference between their separate functions, axial gripping androtative fixing of the members, just as in the hexagonal types ownconvergent-walled keyways. Here the radial component force impacts andretains the floor shims and the tangential component force impacts andretains the wall shims. A total of eight keyway areas are thusproportionately pressured; in FIG. 8 for example, those areas contactedby surfaces 37a, 38a, 37, 38, 41, 42, 41a, 42a, as against the fourareas in the key itself; and there can be no pressure change at any oneor between any opposing pair of areas without corresponding change atall eight.

It will be understood that all of the filler and shim uses of FIGS. 9and 10 may be applied with either type of the hexagonal keys; that is,that the lateral fillers of FIG. 9 for size substitution may be appliedas well with the wedge hexagon key of the first and fourthconstructions, and that the recourse shimmings of FIG. 10 may be appliedwith the expanding hexagon key of the secand and third constructions. Idesire it to be understood that I may practice the invention with allsuch variations of construction as may fall within the spirit of theinvention and the scope of the appended claims such as: the proportionsand supplemental angle of the' triangular adapters, the use of lateralshims of unequal thickness either for convenience of installation or foralternation of index of the keyed members, and means for fastening theauxiliary pieces in place.

I claim:

1. In combination, two machine members having mutually contactingsurfaces, two co-operative channelshaped keyways formed in saidsurfaces, each keyway having two sidewalls in parallel planes; ahexagonal and laterally expandable key having two convergent pressurefaces extending into each keyway; and two triangular adapter pieceswithin the confines of each keyway each having one face parallel withone of said key pressure faces and one face parallel with one of saidkeyway walls, whereby expansive force of said key may be transmitted andratably maintained between said key and all four of the walls of saidkeyways.

2. In combination, two machine members having mutually contactingsurfaces; two co-operative channelshaped keyways formed in saidsurfaces, each keyway having two sidewalls in parallel planes, ahexagonal and vertically wedging key having two convergent pressurefaces extending into each keyway; and two substantially triangularadapter pieces within the confines of each keyway each having one facelongitudinally parallel with one of said key pressure faces and one facelongitudinally parallel with one of said keyway walls, whereby wedgingforce of said key may be transmitted and ratably maintained between saidkey and all four walls of said keyways.

3. The invention defined in claim 2, wherein one of said keyways has itsfloor extending at an acute angle to the floor of the other keyway.

References Cited UNITED STATES PATENTS 408,835 8/1889 Grafton 287-52.05867,468 10/1907 Von Bechtolsheim 287-5205 1,435,811 11/1922 Cuntala28752.05

10 2,989,328 6/1961 Nitchie 287-52.05 2,994,548 8/1961 McGogy 287-5205CARL W. TOMLIN, Primary Examiner.

15 A. V. KUNDRAT, Assistant Examiner.

1. IN COMBINATION, TWO MACHINE MEMBERS HAVING MUTUALLY CONTACTINGSURFACES, TWO CO-OPERATIVE CHANNELSHAPED KEYWAYS FORMED IN SAIDSURFACES, EACH KEYWAY HAVING TWO SIDEWALLS IN PARALLEL PLANES; AHEXAGONAL AND LATERALLY EXPANDABLE KEY HAVING TWO CONVERGENT PRESSUREFACES EXTENDING INTO EACH KEYWAY; AND TWO TRIANGULAR ADAPTER PIECESWITHIN THE CONFINES OF EACH KEYWAY EACH HAVING ONE FACE PARALLEL WITHONE OF SAID KEY PRESSURE FACES AND ONE FACE PARALLEL WITH ONE OF SAIDKEYWAY WALLS, WHEREBY EXPANSIVE FORCE OF SAID KEY MAY BE TRANSMITTED ANDRATABLY MAINTAINED BETWEEN SAID KEY AND ALL FOUR OF THE WALLS OF SAIDKEYWAYS.